Optical member, display device having the same and method of fabricating the same

ABSTRACT

Disclosed are an optical member, a display device including the same, and a method of fabricating the same. The optical member includes a first substrate; a wavelength conversion layer on the first substrate; and a second substrate on the wavelength conversion layer, wherein the wavelength conversion layer includes an oxygen barrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage application of InternationalPatent Application No. PCT/KR2012/006521, filed Aug. 16, 2012, whichclaims priority to Korean Application No. 10-2011-0111679, filed Oct.28, 2011, the disclosures of each of which are incorporated herein byreference in their entirety.

TECHNICAL FIELD

The embodiment relates to an optical member, a display device having thesame, and a method of fabricating the same.

BACKGROUND ART

Some display devices require a backlight unit for generating light todisplay images. The backlight unit is a device for supplying the lightto a display panel including liquid crystal and includes a lightemitting device and means for effectively transferring the light emittedfrom the light emitting device to the liquid crystal.

A light emitting diode (LED) can be used as a light source for thedisplay device. In addition, a light guide plate and optical sheets maybe laminated in the display device to effectively transfer the lightgenerated from the light source to the display panel.

An optical member that converts the wavelength of the light generatedfrom the light source such that white light can be incident into thelight guide plate or the display panel can be employed in the displaydevice. In particular, quantum dots may be used to convert thewavelength of the light.

The quantum dot has a particle size of 10 nm or less and the electricand optical characteristics of the quantum dot may vary depending on theparticle size thereof. For instance, if the quantum dot has the particlesize in the range of about 55 Å to about 65 Å, light having a red colorcan be emitted. In addition, if the quantum dot has the particle size inthe range of about 40 Å to about 50 Å, light having a green color can beemitted and if the quantum dot has the particle size in the range ofabout 20 Å to about 35 Å, light having a blue color can be emitted. Thequantum dot emitting light having a yellow color may have theintermediate particle size between the particle sizes of the quantumdots emitting the red and green colors. The color of the spectrumaccording to the wavelength of the light tends to be shifted from thered color to the blue color, so it is estimated that the size of thequantum dot may be sequentially changed from 65 Å to 20 Å and thisnumerical values may be slightly changed.

In order to form the optical member including the quantum dots, thequantum dots emitting RGB colors, which are the three primary colors ofthe light, or RYGB colors are spin-coated or printed on a transparentsubstrate, such as a glass substrate. If the quantum dot emitting theyellow color is added, the white light approximate to natural light canbe obtained. A matrix (medium) which disperses and carries the quantumdots may emit the light having the visible ray band and the ultravioletray band (including far UV band) and may employ an inorganic substanceor a polymer representing superior transmittance for the light havingthe visible ray band. For instance, the organic substance or the polymermay include inorganic silica, polymethylmethacrylate (PMMA),polydimethylsiloxane (PDMS), poly lactic acid (PLA), silicon polymer orYAG.

A display device employing such a quantum dot is disclosed in KoreanUnexamined Patent Publication No. 10-2011-0012246.

DISCLOSURE OF INVENTION Technical Problem

The embodiment provides an optical member having improved reliabilityand durability, a display device and a method of fabricating the same.

Solution to Problem

An optical member according to the embodiment includes a firstsubstrate; a wavelength conversion layer on the first substrate; and asecond substrate on the wavelength conversion layer, wherein thewavelength conversion layer includes an oxygen barrier.

A display device according to the embodiment includes a light source; awavelength conversion member to which light emitted from the lightsource is incident; and a display panel to which light output from thewavelength conversion member is incident, wherein the wavelengthconversion member includes a first substrate; a wavelength conversionlayer on the first substrate; and a second substrate on the wavelengthconversion layer, and wherein the wavelength conversion layer includes aphosphor.

A method of fabricating an optical member according to the embodimentincludes the steps of forming a wavelength conversion layer including anoxygen barrier on the first substrate; forming a second substrate on thewavelength conversion layer; and heat-treating the wavelength conversionlayer.

Advantageous Effects of Invention

The optical member and the display device according to the embodimentinclude the oxygen barrier contained in the wavelength conversion layer.Thus, the amount of oxygen introduced into the wavelength conversionlayer can be reduced and the wavelength conversion particles included inthe wavelength conversion layer may not be modified.

In particular, the oxygen barrier is diffused by heat and bonded with apolymer included in the first substrate and/or the second substrate.Thus, air-tightness of the first and second substrates can be improved,so the optical member and the display device according to the embodimentmay have the improved reliability.

In addition, the oxygen barrier includes the flame retardant. Thus, theoxygen barrier can be bonded with the polymer contained in the first andsecond substrates and/or the wavelength conversion layer during the heattreatment process. Therefore, the optical member and the display deviceaccording to the embodiment may have the superior oxygen barriercharacteristic and heat-resistance characteristic.

As a result, the optical member and the display device according to theembodiment may have superior durability and reliability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a liquid crystal displayaccording to the first embodiment;

FIG. 2 is a perspective view showing a wavelength conversion memberaccording to the first embodiment;

FIG. 3 is a sectional view taken along line A-A′ of FIG. 2;

FIG. 4 is an exploded perspective view showing a liquid crystal displayaccording to the second embodiment;

FIG. 5 is a perspective view showing a wavelength conversion memberaccording to the second embodiment;

FIG. 6 is a sectional view taken along line B-B′ of FIG. 5;

FIG. 7 is a sectional view showing a light guide plate, a light emittingdiode and a wavelength conversion member according to the secondembodiment;

FIGS. 8 to 10 are views showing the method of fabricating a wavelengthconversion member according to the second embodiment;

FIG. 11 is an exploded perspective view showing a liquid crystal displayaccording to the third embodiment;

FIG. 12 is a perspective view showing a wavelength conversion memberaccording to the third embodiment;

FIG. 13 is a sectional view taken along line C-C′ of FIG. 12; and

FIG. 14 is a sectional view showing a light guide plate, a lightemitting diode and a wavelength conversion member according to thefourth embodiment.

MODE FOR THE INVENTION

In the description of the embodiments, it will be understood that when asubstrate, a frame, a sheet, a layer or a pattern is referred to asbeing “on” or “under” another substrate, another frame, another sheet,another layer, or another pattern, it can be “directly” or “indirectly”on the other substrate, frame, sheet, layer, or pattern, or one or moreintervening layers may also be present. Such a position of the layer hasbeen described with reference to the drawings. The thickness and size ofeach layer shown in the drawings may be exaggerated, omitted orschematically drawn for the purpose of convenience or clarity. Inaddition, the size of elements does not utterly reflect an actual size.

FIG. 1 is an exploded perspective view showing a liquid crystal displayaccording to the first embodiment, FIG. 2 is a perspective view showinga wavelength conversion member according to the first embodiment, andFIG. 3 is a sectional view taken along line A-A′ of FIG. 2.

Referring to FIGS. 1 to 3, the liquid crystal display (LCD) according tothe embodiment includes a backlight unit 10 and a liquid crystal panel20.

The backlight unit 10 supplies light to the liquid crystal panel 20. Thebacklight unit 10 serves as a surface light source so that the light canbe uniformly supplied to a bottom surface of the liquid crystal panel20.

The backlight unit 10 is disposed below the liquid crystal panel 20. Thebacklight unit 10 includes a bottom cover 100, a light guide plate 200,a reflective sheet 300, a light source, such as a plurality of lightemitting diodes 400, a printed circuit board 401, and a plurality ofoptical sheets 500.

The upper portion of the bottom cover 100 is open. The bottom cover 100receives the light guide plate 200, the light emitting diodes 400, theprinted circuit board 401, the reflective sheet 300, and the opticalsheets 500 therein.

The light guide plate 200 is disposed in the bottom cover 100 andarranged on the reflective sheet 300. The light guide plate 200 guidesthe light upward by totally-reflecting, refracting and scattering thelight incident thereto from the light emitting diodes 400.

The reflective sheet 300 is disposed below the light guide plate 200. Inmore detail, the reflective sheet 300 is disposed between the lightguide plate 200 and the bottom surface of the bottom cover 100. Thereflective sheet 300 reflects the light upward as the light is outputdownward from the bottom surface of the light guide plate 200.

The light emitting diodes 400 serve as a light source for generating thelight. The light emitting diodes 400 are disposed at one lateral side ofthe light guide plate 200. The light generated from the light emittingdiodes 400 is incident into the light guide plate 200 through thelateral side of the light guide plate 200.

The light emitting diodes 400 may include a blue light emitting diodegenerating the blue light or a UV light emitting diode generating the UVlight. In detail, the light emitting diodes 400 may emit the blue lighthaving the wavelength band of about 430 nm to about 470 nm or the UVlight having the wavelength band of about 300 nm to abut 400 nm.

The light emitting diodes 400 are mounted on the printed circuit board401. The light emitting diodes 400 may be disposed under the printedcircuit board 401. The light emitting diodes 400 are driven by receivinga driving signal through the printed circuit board 401.

The printed circuit board 401 is electrically connected to the lightemitting diodes 400. The printed circuit board 401 may mount the lightemitting diodes 400 thereon. The printed circuit board 401 is disposedin the bottom cover 100.

The optical sheets 500 are disposed on the light guide plate 200. Theoptical sheets 500 supplies the light to the liquid crystal panel 20 bychanging or enhancing the optical property of the light output from thetop surface of the light guide plate 200.

The optical sheets 500 may include a wavelength conversion member 501, adiffusion sheet 502, a first prism sheet 503, and a second prism sheet503.

The wavelength conversion member 501 is provided on a light path betweenthe light source 400 and the liquid crystal panel 20. For instance, thewavelength conversion member 501 is provided on the light guide plate200. In detail, the wavelength conversion member 501 is interposedbetween the light guide plate 200 and the diffusion sheet 502. Thewavelength conversion member 501 converts the wavelength of the incidentlight and outputs the incident light upward.

For instance, if the light emitting diodes 400 are blue light emittingdiodes, the wavelength conversion member 501 converts the blue lightoutput upward from the light guide plate 200 into the green light andthe red light. In detail, the wavelength conversion member 501 convertsa part of the blue light into the green light having the wavelength inthe range of about 520 nm to about 560 nm, and a part of the blue lightinto the red light having the wavelength in the range of about 630 nm toabout 660 nm.

Therefore, the white light may be generated by the light passing throughthe wavelength conversion member 501 without being converted and thelights converted by the wavelength conversion member 501. In detail, thewhite light can be incident into the liquid crystal panel 20 through thecombination of the blue light, the green light and the red right.

In other words, the wavelength conversion member 501 is an opticalmember that converts the characteristic of the incident light. Thewavelength conversion member 501 may have a sheet shape. That is, thewavelength conversion member 501 is an optical sheet.

As shown in FIGS. 2 and 3, the wavelength conversion member 501 includesa lower substrate 510, an upper substrate 520, a wavelength conversionlayer 530, and a sealing part 540.

The lower substrate 510 is provided under the wavelength conversionlayer 530. The lower substrate 510 may be transparent and flexible. Thelower substrate 510 may adhere to a bottom surface of the wavelengthconversion layer 530.

The upper substrate 520 is disposed on the wavelength conversion layer530. The upper substrate 520 may be transparent and flexible. The uppersubstrate 520 may adhere to the top surface of the wavelength conversionlayer 530.

The wavelength conversion layer 530 is sandwiched between the upper andlower substrates 520 and 510. The upper and lower substrates 520 and 510support the wavelength conversion layer 530. The upper and lowersubstrates 520 and 510 protect the wavelength conversion layer 530 fromexternal physical impact. The upper and lower substrates 520 and 510directly make contact with the wavelength conversion layer 530.

In addition, the upper and lower substrates 520 and 510 have low oxygenpermeability and low moisture permeability. Thus, the upper and lowersubstrates 520 and 510 can protect the wavelength conversion layer 530from external chemical impact by oxygen and/or moisture.

The wavelength conversion layer 530 is interposed between the lower andupper substrates 510 and 520. The wavelength conversion layer 530 mayadhere to the top surface of the lower substrate 510, and adhere to thebottom surface of the upper substrate 520.

The wavelength conversion layer 530 includes a host layer 531 and aplurality of wavelength conversion particles 532. In addition, thewavelength conversion layer 530 may further include an oxygen barrier.

The host layer 531 surrounds the wavelength conversion particles 532.That is, the wavelength conversion particles 532 are uniformlydistributed in the host layer 531. The host layer 531 may include apolymer, such as a silicon resin. The host layer 531 is transparent.That is, the host layer 531 may be formed by using a transparentpolymer.

The host layer 531 is interposed between the lower and upper substrates510 and 520. In more detail, the host layer 531 adheres to the topsurface of the lower substrate 510 and the bottom surface of the uppersubstrate 520.

The wavelength conversion particles 532 are interposed between the lowerand upper substrates 510 and 520. In more detail, the wavelengthconversion particles 532 are uniformly distributed in the host layer531, and the host layer 531 is interposed between the lower substrate510 and the upper substrate 520. The wavelength conversion particles 532may be distributed in the host layer 531 in the concentration of about0.5 wt % to about 5 wt %.

The wavelength conversion particles 532 convert the wavelength of thelight emitted from the light emitting diodes 400. In detail, thewavelength conversion particles 532 receive light emitted from the lightemitting diodes 400 to convert the wavelength of the incident light. Forinstance, the wavelength conversion particles 532 may convert the bluelight emitted from the light emitting diodes 400 into the green lightand the red light. That is, the wavelength conversion particles 532 mayconvert the blue light into the green light having the wavelength in therange of about 500 nm to about 600 nm or into the red light having thewavelength in the range of about 630 nm to about 660 nm.

The wavelength conversion particles 532 may include compoundsemiconductors. In detail, the wavelength conversion particles 532 mayinclude nano particles including the compound semiconductors. In moredetail, the wavelength conversion particles 532 may include quantum dots(QD). The quantum dots may include core nano-crystals and shellnano-crystals surrounding the core nano-crystals. In addition, thequantum dots may include organic ligands bonded to the shellnano-crystals. Further, the quantum dots may include an organic coatinglayer surrounding the shell nano-crystals.

The shell nano-crystals may be prepared as at least two layers. Theshell nano-crystals are formed on the surface of the core nano-crystals.The quantum dots lengthen the wavelength of the light incident into thecore nano-crystals by using the shell nano-crystals forming a shelllayer, thereby improving the light efficiency.

The quantum dots may include at least one of a group-II compoundsemiconductor, a group-III compound semiconductor, a group-V compoundsemiconductor, and a group-VI compound semiconductor. In more detail,the core nano-crystals may include CdSe, InGaP, CdTe, CdS, ZnSe, ZnTe,ZnS, HgTe or HgS. In addition, the shell nano-crystals may includeCuZnS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS. The quantum dotmay have a diameter of about 1 nm to about 10 nm.

The wavelength of the light emitted from the quantum dots can beadjusted according to the size of the quantum dots. The organic ligandmay include pyridine, mercapto alcohol, thiol, phosphine and phosphineoxide. The organic ligand may stabilize the unstable quantum dots afterthe synthesis process. Dangling bonds may be formed at the valence bandand the quantum dots may be unstable due to the dangling bonds. However,since one end of the organic ligand is the non-bonding state, the oneend of the organic ligand is bonded with the dangling bonds, therebystabilizing the quantum dots.

In particular, if the size of the quantum dot is smaller than the Bohrradius of an exciton, which consists of an electron and a hole excitedby light and electricity, the quantum confinement effect may occur, sothat the quantum dot may have the discrete energy level. Thus, the sizeof the energy gap is changed. In addition, the charges are confinedwithin the quantum dot, so that the light emitting efficiency can beimproved.

Different from general fluorescent pigments, the fluorescent wavelengthof the quantum dot may vary depending on the size of the particles. Indetail, the light has the shorter wavelength as the size of the particleis reduced, so that the fluorescent light having the wavelength band ofvisible ray can be generated by adjusting the size of the particles. Inaddition, the quantum dot represents the extinction coefficient which is100 to 1000 times higher than that of the general pigment and has thesuperior quantum yield as compared with the general pigment, so thatstrong fluorescent light can be generated.

The quantum dots can be synthesized through the chemical wet scheme. Thechemical wet scheme is to grow the particles by immersing the precursormaterial in the organic solvent. According to the chemical wet scheme,the quantum dots can be synthesized.

The oxygen barrier is included in the wavelength conversion layer 530.In detail, the oxygen barrier is distributed in the wavelengthconversion layer 530. In addition, the oxygen barrier can be containedin the first substrate 510 and/or the second substrate 520.

The oxygen barrier is used to improve the oxygen barrier characteristicand the heat-resistance characteristic of the lower substrate 510, theupper substrate 520 and/or the wavelength conversion layer 530. Indetail, the oxygen barrier is bonded with the polymer included in thelower substrate 510, the upper substrate 520 and/or the wavelengthconversion layer 530 to improve the oxygen barrier characteristic andthe heat-resistance characteristic of the lower substrate 510, the uppersubstrate 520 and/or the wavelength conversion layer 530. In moredetail, the oxygen barrier is diffused and decomposed by heat so thatthe oxygen barrier can be bonded with the polymer included in the lowersubstrate 510, the upper substrate 520 and/or the wavelength conversionlayer 530.

The oxygen barrier may include a flame retardant. For instance, theoxygen barrier can be selected from a halogen-based flame retardant anda phosphor-based flame retardant. In detail, the oxygen barrier mayinclude the phosphor-based flame retardant. In more detail, the oxygenbarrier may include a phosphate-based flame retardant.

The oxygen barrier can be expressed as following chemical formula 1.

In chemical formula 1, P is phosphor, O is oxygen, and R1, R2 and R3 areindependently selected from oxygen, a substituted or non-substitutedaryl group, a substituted or non-substituted alkoxy group, and asubstituted or non-substituted hetero aryl group. In detail, the R1, R2and R3 are a substituted or non-substituted aryl group.

The oxygen barrier may include bisphenol-A bis(diphenyl phosphate)expressed as following chemical formula 2.

In addition, the oxygen barrier may include resorcinol bis(diphenylphosphate) expressed as following chemical formula 3.

Further, the oxygen barrier may include the phosphor-based flameretardant, such as Ammonium Polyphosphate (APP),Tris(2-chloroethyl)Phosphate (TCEP), Isopropylphenyl Diphenyl Phosphate(IPPP), Triphenyl Phosphate (TPP), Triethyl Phosphate (TEP), Resorcinoldi phosphate (RDP), or Tricresyl Phosphate (TCP).

The oxygen barrier can be decomposed into the radical in thehigh-temperature condition. Especially, if the oxygen barrier is thephosphor-based flame retardant, the oxygen barrier may be decomposed atthe temperature of about 100° C. to about 250° C.

The lower substrate 510 and the upper substrate 520 may include atransparent polymer, such as polyethylene terephthalate. In addition,the lower substrate 510 and/or the upper substrate 520 may include apolymer bonded with radicals decomposed from the oxygen barrier.

For instance, the lower substrate 510 and/or the upper substrate 520 mayinclude a polymer substituted with radicals derived from the oxygenbarrier. In detail, the lower substrate 510 and/or the upper substrate520 may include a polymer including a functional group containingphosphor. In more detail, the lower substrate 510 and/or the uppersubstrate 520 may include a polymer substituted with a phosphite group.For instance, the lower substrate 510 and/or the upper substrate 520 mayinclude substituted polyethylene terephthalate expressed as followingchemical formula 4.

In chemical formula 4, R1 and R3 are independently selected from oxygen,a substituted or non-substituted aryl group, a substituted ornon-substituted alkoxy group, and a substituted or non-substitutedhetero aryl group. In detail, the R1 and R3 are a substituted ornon-substituted aryl group. In addition, n is in the range of 1 to10,000.

In contrast, the lower substrate 510 and/or the upper substrate 520 mayinclude a polymer substituted with a phosphate group.

The sealing part 540 is disposed at the lateral side of the wavelengthconversion layer 530. In detail, the sealing part 540 covers the lateralside of the wavelength conversion layer 530. In more detail, the sealingpart 540 can also be disposed at the lateral sides of the lowersubstrate 510 and the upper substrate 520. In this case, the sealingpart 540 covers the lateral sides of the lower substrate 510 and theupper substrate 520.

In addition, the sealing part 540 may be bonded to the lateral sides ofthe wavelength conversion layer 530, the lower substrate 510 and theupper substrate 520. In addition, the sealing part 540 may closelyadhere to the lateral sides of the wavelength conversion layer 530, thelower substrate 510 and the upper substrate 520.

Therefore, the sealing part 540 can seal the lateral side of thewavelength conversion layer 530. That is, the sealing part 540 may serveas a protective part for protecting the wavelength conversion layer 530from the external chemical impact.

The wavelength conversion member 501 can be formed through the followingprocess.

First, wavelength conversion particles 532 and the oxygen barrier areuniformly distributed in the silicon resin, epoxy resin or acryl resin.At this time, the oxygen barrier can be mixed in the ratio of about 0.1wt % to about 5 wt %.

Then, the resin composition is uniformly coated on the lower substrate510. The resin composition may be coated on the top surface of the lowersubstrate 510 through the slit coating, spin coating or spray coating.

After that, the coated resin composition is cured by light and/or heat,so that the wavelength conversion layer 530 is formed.

Thereafter, the upper substrate 520 is laminated on the upper substrate520 and then the sealing part 540 is formed.

Then, the wavelength conversion layer 530 is subject to the heattreatment process. Especially, if the oxygen barrier is thephosphor-based flame retardant, the wavelength conversion layer 530 issubject to the heat treatment process for about 10 seconds to about 10minutes at the temperature of about 100° C. to about 250° C. Thetemperature and the time of the heat treatment process for thewavelength conversion layer 530 may vary depending on the type of theoxygen barriers.

Therefore, the oxygen barrier included in the wavelength conversionlayer 530 is decomposed and diffused by heat. In particular, the oxygenbarrier is diffused into the lower substrate 510 and the upper substrate520. In addition, a part of the oxygen barrier may remain in thewavelength conversion layer 530 without being diffused.

The radical can be formed as the oxygen barrier is decomposed by theheat. The radical is bonded with the polymer included in the lowersubstrate 510 and/or the upper substrate 520, thereby improving thecompactness of the lower substrate 510 and the upper substrate 520.Therefore, the lower substrate 510 and the upper substrate 520 caneffectively block the moisture and oxygen introduced thereto from theoutside. In addition, since the oxygen barrier includes the flameretardant, the lower substrate 510 and the upper substrate 520 can moreeffectively block the oxygen introduced thereto from the outside.

Then, the sealing part 540 is formed at the lateral sides of the lowersubstrate 510, the upper substrate 520 and the wavelength conversionlayer 530.

In this manner, the wavelength conversion member 501 can be formed.

In addition, the wavelength conversion member 501 may further includefirst and second inorganic protective layers. The first inorganicprotective layer is coated on the bottom surface of the lower substrate510 and the second inorganic protective layer is coated on the topsurface of the upper substrate 520. The first and second inorganicprotective layers may include silicon oxides.

The diffusion sheet 502 is disposed on the wavelength conversion member501. The diffusion sheet 502 may improve the uniformity of light passingthrough the diffusion sheet 502. The diffusion sheet 502 may include aplurality of beads.

The first prism sheet 503 is provided on the diffusion sheet 502. Thesecond prism sheet 504 is provided on the first prism sheet 503. Thefirst prism sheet 503 and the second prism sheet 504 may improve thelinearity of light passing therethrough.

The liquid crystal panel 20 is disposed on the optical sheets 500. Inaddition, the liquid crystal panel 20 is disposed on the panel guide 23.The liquid crystal panel 20 is guided by the panel guide 23.

The liquid crystal panel 20 displays images by adjusting intensity oflight passing through the liquid crystal panel 20. In detail, the liquidcrystal panel 20 is a display panel for displaying the images by usingthe light emitted from the backlight unit 10. The liquid crystal panel20 includes a TFT substrate 21, a color filter substrate 22 and a liquidcrystal layer interposed between the two substrates. In addition, theliquid crystal panel 20 includes polarizing filters.

Hereinafter, the TFT substrate 21 and the color filter substrate 22 willbe described in detail although they are not shown in the drawings indetail. The TFT substrate 21 includes a plurality of gate lines and aplurality of data lines crossing the gate lines to define pixels and athin film transistor (TFT) is provided at each cross section such thatthe thin film transistor TFT can be connected to a pixel electrode ofthe pixel in one-to-one correspondence. The color filter substrate 22includes color filters having R, G and B colors corresponding to thepixels, a black matrix covering the gate lines, data lines and thin filmtransistors within the limit of the color filters, and a commonelectrode covering the above elements.

A driving PCB 25 is provided at an outer peripheral portion of theliquid crystal panel 20 to supply driving signals to the gate lines anddata lines.

The driving PCB 25 is electrically connected to the liquid crystal panel20 by a COF (chip on film) 24. The COF 24 may be replaced with a TCP(tape carrier package).

As described above, in the liquid crystal display, the oxygen barrier isincluded in the wavelength conversion layer 530. Thus, the amount ofoxygen introduced into the wavelength conversion layer 530 can bereduced and the wavelength conversion particles may not be modified.

Especially, the oxygen barrier is diffused by the heat and bonded withthe polymer included in the lower substrate 510 and/or the uppersubstrate 520. Thus, the air-tightness of the lower substrate 510 andthe upper substrate 520 can be improved, so the liquid crystal displayaccording to the embodiment may have the improved reliability.

In addition, since the flame retardant is used as the oxygen barrier,the oxygen barrier may be bonded with the polymer included in the lowersubstrate 510, the upper substrate 520 and/or the wavelength conversionlayer 530 during the heat treatment process. Therefore, the wavelengthconversion member 501 may have the superior oxygen barriercharacteristic and the heat-resistance characteristic.

As a result, the liquid crystal display according to the embodiment mayhave the improved durability and reliability.

FIG. 4 is an exploded perspective view showing a liquid crystal displayaccording to the second embodiment, FIG. 5 is a perspective view showinga wavelength conversion member according to the second embodiment, FIG.6 is a sectional view taken along line B-B′ of FIG. 5, FIG. 7 is asectional view showing a light guide plate, a light emitting diode and awavelength conversion member according to the second embodiment, andFIGS. 8 to 10 are views showing the method of fabricating a wavelengthconversion member according to the second embodiment. In the descriptionabout the second embodiment, the description about the liquid crystaldisplay according to the previous embodiment will be basicallyincorporated by reference except for the modified parts.

Referring to FIGS. 4 to 7, the wavelength conversion member 600 isdisposed between the light emitting diodes 400 and the light guide plate200.

The wavelength conversion member 600 may extend in one direction. Indetail, the wavelength conversion member 600 may extend along onelateral side of the light guide plate 200. In more detail, thewavelength conversion member 600 may extend along an incident surface ofthe light guide plate 200.

The wavelength conversion member 600 receives light emitted from thelight emitting diodes 400 to convert the wavelength of the incidentlight. For instance, the wavelength conversion member 600 may convertthe blue light emitted from the light emitting diodes 400 into the greenlight and the red light. That is, the wavelength conversion member 600may convert a part of the blue light into the green light having thewavelength in the range of about 520 nm to about 560 nm and convert apart of the blue light into the red light having the wavelength in therange of about 630 nm to about 660 nm.

Therefore, the white light may be generated by the light passing throughthe wavelength conversion member 600 and the lights converted by thewavelength conversion member 600. In detail, the white light can beincident into the light guide plate 200 through the combination of theblue light, the green light and the red right.

As shown in FIGS. 5 to 7, the wavelength conversion member 600 includesa lower substrate 610, an upper substrate 620, a wavelength conversionlayer 630, and a sealing part 640.

As shown in FIG. 6, the lower substrate 610 is provided under thewavelength conversion layer 630. The lower substrate 610 may betransparent and flexible. The lower substrate 610 may adhere to a bottomsurface of the wavelength conversion layer 630.

The upper substrate 620 is disposed on the wavelength conversion layer630. The upper substrate 620 may be transparent and flexible. The uppersubstrate 620 may adhere to the top surface of the wavelength conversionlayer 630.

In addition, as shown in FIG. 7, the lower substrate 610 faces the lightemitting diodes 400. That is, the lower substrate 610 is disposedbetween the light emitting diodes 400 and the wavelength conversionlayer 630. In addition, the upper substrate 620 faces the light guideplate 200. That is, the upper substrate 620 is disposed between thewavelength conversion layer 630 and the light guide plate 200.

The wavelength conversion layer 630 is sandwiched between the upper andlower substrates 620 and 610. In addition, the sealing part 640 coversthe lateral side of the wavelength conversion layer 630. The upper andlower substrates 620 and 610 support the wavelength conversion layer630. In addition, the upper and lower substrates 620 and 610 and thesealing part 540 may protect the wavelength conversion layer 630 fromthe external physical and chemical impact.

The wavelength conversion member according to the present embodiment canbe formed through the following process.

Referring to FIG. 8, a resin composition including a plurality ofwavelength conversion particles 632 and the oxygen barrier is coated ona first transparent substrate 611. Then, the resin composition is curedby light and/or heat so that a preliminary wavelength conversion layer635 is formed on the first transparent substrate 611.

Then, a second transparent substrate 621 is laminated on the preliminarywavelength conversion layer 635.

After that, the preliminary wavelength conversion layer 635 is subjectto the heat treatment process and the oxygen barrier included in thepreliminary wavelength conversion layer 635 is diffused and decomposedby the heat. In addition, the decomposed oxygen barrier is bonded withthe polymer included in the first transparent substrate 611 and/or thesecond transparent substrate 621.

Referring to FIG. 9, the first transparent substrate 611, thepreliminary wavelength conversion layer 635 and the second transparentsubstrate 621 are simultaneously cut. Therefore, a plurality ofpreliminary wavelength conversion members 601 can be formed. Each of thepreliminary wavelength conversion members 601 may include the lowersubstrate 610, the wavelength conversion layer 630 and the uppersubstrate 620. Since the lower substrate 610, the wavelength conversionlayer 630 and the upper substrate 620 are simultaneously cut through thecutting process, the lower substrate 610, the wavelength conversionlayer 630 and the upper substrate 620 may have cutting surfaces 605aligned on the same plane.

Referring to FIG. 10, the preliminary wavelength conversion members 601are aligned such that the lower substrate 610 may face the uppersubstrate 620. Then, the sealing part 640 is formed at the lateral sidesof the preliminary wavelength conversion members 601, that is, at thecutting surface 605.

After that, the wavelength conversion members 601 may be separated fromeach other.

In the liquid crystal display according to the present embodiment, thewavelength conversion layer 630 has a relatively small size. Thus, asmaller amount of wavelength conversion particles 632 can be used tofabricate the liquid crystal display according to the presentembodiment.

Therefore, the liquid crystal display according to the presentembodiment can reduce the amount of the wavelength conversion particles632 and can be readily fabricated at the low cost.

FIG. 11 is an exploded perspective view showing a liquid crystal displayaccording to the third embodiment. FIG. 12 is a perspective view showinga wavelength conversion member according to the third embodiment. FIG.13 is a sectional view taken along line C-C′ of FIG. 12. FIG. 14 is asectional view showing a light guide plate, a light emitting diode and awavelength conversion member according to the third embodiment. In thedescription about the third embodiment, the description about the liquidcrystal display according to the previous embodiments will be basicallyincorporated by reference except for the modified parts.

Referring to FIGS. 11 to 14, the liquid crystal display according to thepresent embodiment includes a plurality of wavelength conversion members700. The wavelength conversion members 700 correspond to the lightemitting diodes 400, respectively.

In addition, the wavelength conversion members 700 are disposed betweenthe light emitting diodes 400 and the light guide plate 200. That is,each of the wavelength conversion members 700 is disposed between thecorresponding light emitting diode and the light guide plate 200.

The wavelength conversion members 700 may have surface areas larger thansurface areas of the light emitting diodes 400. Thus, most of the lightemitted from each light emitting diode may be incident into thecorresponding wavelength conversion member 700.

In addition, as shown in FIGS. 12 to 14, each of the wavelengthconversion members 700 may include a lower substrate 710, an uppersubstrate 720, a wavelength conversion layer 730 and a sealing part 740.

The features of the lower substrate 710, the upper substrate 720, thewavelength conversion layer 730 and the sealing part 740 aresubstantially identical to those of the previous embodiments.

In the liquid crystal display according to the present embodiment, thewavelength conversion layer 730 has a relatively small size. Thus, asmaller amount of wavelength conversion particles 732 can be used tofabricate the liquid crystal display according to the presentembodiment.

Therefore, the liquid crystal display according to the presentembodiment can reduce the amount of the wavelength conversion particles732 and can be readily fabricated at the low cost.

In addition, the feature of each wavelength conversion member 700 can bemodified suitably for the corresponding light emitting diode 400. Thus,the liquid crystal display according to the embodiment may have thesuperior reliability, brightness, and color reproduction.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effects such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

The invention claimed is:
 1. An optical member comprising: a wavelengthconversion layer; a first substrate under the wavelength conversionlayer; a second substrate on the wavelength conversion layer; a firstinorganic protective layer coated on a bottom surface of the firstsubstrate; a second inorganic protective layer coated on a top surfaceof the second substrate; and a sealing part disposed at a lateralsurface of the wavelength conversion layer, wherein the wavelengthconversion layer includes an oxygen barrier, wherein the wavelengthconversion layer comprises a host and quantum dots in the host, whereinthe host includes a silicon resin, wherein the first and secondinorganic protective layers include a silicon oxide, wherein the firstand second substrates include a polyethylene terephthalate, wherein thefirst and second substrates are transparent, wherein the first substratecomprises a top surface, the bottom surface, and a lateral surfaceconnecting the top surface to the bottom surface; wherein the secondsubstrate comprises the top surface, a bottom surface, and a lateralsurface connecting the top surface to the bottom surface; wherein thetop surface of the first substrate is in direct physical contact with abottom surface of the host, wherein the bottom surface of the secondsubstrate is in direct physical contact with a top surface of the host,wherein the sealing part is in direct physical contact with a lateralsurface of the host, wherein the sealing part is in direct physicalcontact with the lateral surface of the first substrate and the lateralsurface of the second substrate, wherein the quantum dots aredistributed in the host in a concentration of 0.5 wt % to 5 wt % basedon a total content of the wavelength conversion layer, wherein theoxygen barrier is distributed in the host in a concentration of 0.1 wt %to 5 wt % based on a total content of the wavelength conversion layer,wherein the wavelength conversion layer is subjected to a heat treatmentprocess at a temperature of 100° C. to 250° C., wherein the oxygenbarrier included in the wavelength conversion layer is decomposed byheat, and wherein the oxygen barrier is diffused into the first andsecond substrates by heat, and a part of the oxygen barrier remains inthe host; wherein radicals are formed as the oxygen barrier isdecomposed by the heat, and the radicals bond with a polymer included inthe first substrate, a polymer included in the second substrate, and apolymer included in host; and wherein each of the first substrate andthe second substrate includes substituted polyethylene terephthalateexpressed as the following chemical formula 4:

where each of R₁ and R₃ is a substituted or non-substituted aryl group,and n is in a range of from 1 to 10,000.
 2. The optical member of claim1, wherein the oxygen barrier includes a flame retardant containing aphosphor.
 3. The optical member of claim 1, wherein the first substrateor the second substrate includes a phosphor.
 4. The optical member ofclaim 3, wherein the first substrate or the second substrate includes apolymer having a phosphite group.